1. Field of the Invention
The invention relates to a novel process for extracting and separating simmondsins from jojoba meal.
2. Description of the Prior art
Jojoba, Simmondsia chinensis (Link) Schneider, is native to the desert Southwestern United States and Mexico. It is currently being grown on 8,000 to 12,000 acres in the U.S. and elsewhere worldwide. Jojoba has a unique wax ester oil which is 50 to 60% of its seed weight. This oil is currently used in cosmetics and lubricants. The remainder of the seed is not used as much as the oil, even though it contains about 25% crude protein after the oil is removed. The defatted meal contains sugars and 11-15% of a unique group of natural products, all structurally related to simmondsin. Cokeleare et al. (1995, Ind. Crops Prod., 4:91-96) have shown that simmondsin is an effective hunger satiation agent and reduces food intake in mice, rats and chickens. Jojoba meal has been used for its simmondsin content to regulate food intake of animals, but the meal also contains other antinutritional factors such as trypsin inhibitor, polyphenols, bitter taste, nonnutritive protein and indigestible jojoba oil.
The isolation of simmondsin was first described by Elliger et al. (1973, J. Chem. Soc., Perkin Trans., 1:2209-2212) who extracted it with ethyl acetate from the ground seed whose oil had been removed with hexane. Many other solvent combinations have since been tested for removal of simmondsin and its analogues from the defatted (oil-free) ground seed meal, with the goal of complete extraction of all simmondsin analogues. Cotageorge et al. (1978, Detoxification of jojoba meal. In: Yermanos (Ed.), Proceedings of the Third International Conference on Jojoba, Riverside, Calif. University of California. pp. 171-184) used water, 90% ethanol and methanol. Water was found to extract all of the simmondsins but repeated extractions with methanol or 90% ethanol were insufficient to remove all of the simmondsins from the defatted jojoba meal. More recently, Erhan et al. (1997, Ind. Crops Prod., 6:147-154) disclosed a process for the water extraction of jojoba meal which produced a concentrate containing 42% simmondsin and related substances. Medina et al. (1988, Elimination of toxic compounds, nutritional evaluation and partial characterization of protein from jojoba meal. In: Baldwin (Ed.), Production, Processing and Utilization of Jojoba, Am. Oil Chem. Soc., Champaign, Ill., pp. 423-429) used isopropanol-water in various ratios to extract simmondsins and tannins from defatted meal. A ratio of 7:3 (isopropanol:water) was found to be optimal for total extraction of simmondsins and partial removal of tannins. Abbott et al. (1988, Monitoring jojoba toxins by Fourier transform infrared spectroscopy and HPLC, In: Baldwin (Ed.), Production, Processing and Utilization of Jojoba, Am. Oil Chem. Soc., Champaign, Ill., pp. 440-450) reported that a ratio of 9:1 acetonitrile:water extracted the simmondsins completely from defatted meal, and the same solvent could be used to separate the four simmondsin compounds--simmondsin (S), simmondsin ferulate (SF), demethylsimmondsin (DMS) and didemethyl simmondsin (DDMS) individually on an analytical chromatographic column. Verbiscar et al. (1980, J. Agric. Food Chem., 28:571-578) tested acetone, isopropanol, methanol, dichloromethane:methanol in the ratio of 85:15 and water to extract simmondsin or simmondsin ferulate from defatted meal and found that only water and methanol extracted simmondsin and simmondsin ferulate nearly completely. Acetone extraction, followed by preparative silica gel column separation with chloroform, acetone, and chloroform/methanol have been proposed for solvent-based preparation of simmondsin (Van Boven et al., 1993, J. Agric. Food Chem., 41:1605-1607). A similar procedure was used to prepare mg quantities of demethylsimmondsin and didemethyl simmondsin (Van Boven et al., 1996, Isolation by preparative HPLC of simmondsin analogues from jojoba meal, In: Princen and Rossi (Ed.), Proceedings of the IX International Conference on Jojoba and Its Uses, Sep. 26-30, 1994, Catamarca, Argentina. Am. Oil Chem. Soc., Champaign, Ill., pp. 135-136). For quantitative extraction of simmondsin and simmondsin ferulate from jojoba meal and feed samples, methanol or 80/20 acetonitrile/water was found to work best and 1-propanol or other mixtures of acetonitrile and water did not work as well in a column extraction or extraction tube method (Van Boven et al., 1996, J. Agric. Food Chem., 44:2239-2243). Membrane separation processes for isolating both the protein and the low molecular weight components have been reported (Abbott et al., 1991, J. Agric. Food Chem. 39:1488-1493. Abbott, et al., 1996, Processing jojoba meal for value-added products using membrane separations, In: Princen and Rossi (Ed.), Proceedings of the IX International Conference on Jojoba and Its Uses, Sep. 26-30, 1994, Catamarca, Argentina, Am. Oil Chem. Soc., Champaign, Ill., pp. 126-130; Nabetani et al., 1995, Ind. Eng. Chem., 34:1779-1788). Sequential extraction of jojoba meal with isopropanol removed primarily oil in the first sequence and reduced simmondsin and analogues concentration in the meal in a second sequential extraction but ethanol was not suitable for sequential extractions (Hassanen, 1985 Extraction of oilseed model systems with alcohols, PhD Thesis, Texas A&M University, College Station, Tex.).